ScienceDaily (Jan. 21, 2010) - The controversial study on African IQ levels conducted by psychologist Richard Lynn is deeply flawed. This conclusion is the outcome of studies by Jelte Wicherts, Conor Dolan, Denny Borsboom and Han van der Maas of the University of Amsterdam (UvA) and Jerry Carlson of the University of California (Riverside).

Their findings are set to be published in Intelligence, Personality and Individual Differences, and Learning and Individual Differences.

In an oft-quoted literature study conducted in 2006, Lynn concluded that black Africans have an average IQ of less than 70 (compared to an average western IQ of 100). Lynn suggested that these low IQs are indicative of a low intelligence level, claiming this offered an explanation for the low level of economic development in sub-Saharan countries.

Lynn's study is well known among psychologists, and has been referenced by academics such as Nobel laureate James Watson, and the authors of the controversial book The Bell Curve -- Intelligence and Class Structure in America (Richard Herrnstein and Charles Murray: Freepress, 1994).

African IQ scores prove flawed

Wicherts and his colleagues examined over 100 published studies, concluding that there is no evidence to back up Lynn's claims. Amongst other flaws, Lynn used selective data by systematically ignoring Africans with high IQ scores. The researchers also claim that African IQ test scores cannot be interpreted in terms of lower intelligence levels, as these scores have different psychometric characteristics than western IQ test scores. Until now, the incomparability of Western and African IQ scores had never been systematically proven.

The scientists point out that the average African IQ is currently comparable to the average level in the Netherlands around 1950. However, IQ scores in Western countries have risen sharply over the course of the 20th century. In view of this trend, Wicherts and his colleagues claim there are no reasonable grounds to conclude that sub-Saharan countries are poor due to the lower IQ scores of their populations. As it turns out, the average IQ of African adults is seeing a similar rising trend, which is expected to continue if living conditions in Africa improve in future.

aDepartment of Psychology, University of Amsterdam, Roetersstraat 15, 1018 WB Amsterdam, The Netherlands

Received 16 February 2009; revised 19 May 2009; accepted 26 May 2009. Available online 24 June 2009.

Abstract

Kanazawa (2008), Templer (2008), and Templer and Arikawa (2006) claimed to have found empirical support for evolutionary theories of race differences in intelligence by correlating estimates of national IQ with indicators of reproductive strategies, temperature, and geographic distance from Africa. In this paper we criticize these studies on methodological, climatic, and historical grounds. We show that these studies assume that the Flynn Effect is either nonexistent or invariant with respect to different regions of the world, that there have been no migrations and climatic changes over the course of evolution, and that there have been no trends over the last century in indicators of reproductive strategies (e.g., declines in fertility and infant mortality). In addition, we show that national IQs are strongly confounded with the current developmental status of countries. National IQs correlate with all the variables that have been suggested to have caused the Flynn Effect in the developed world.

Evolution, brain size, and the national IQ of peoples around 3000 years B.C

Jelte M. Wicherts a, Denny Borsboom a and Conor V. Dolan a

aUniversity of Amsterdam, Department of Psychology, Amsterdam, The Netherlands

Received 22 August 2009; accepted 26 August 2009. Available online 18 September 2009.

Abstract

In this rejoinder, we respond to comments by Lynn, Rushton, and Templer on our previous paper in which we criticized the use of national IQs in studies of evolutionary theories of race differences in intelligence. We reiterate that because of the Flynn Effect and psychometric issues, national IQs cannot be taken to reflect populations' levels of g as fixed since the last ice age. We argue that the socio-cultural achievements of peoples of Mesopotamia and Egypt in 3000 B.C. stand in stark contrast to the current low level of national IQ of peoples of Iraq and Egypt and that these ancient achievements appear to contradict evolutionary accounts of differences in national IQ. We argue that race differences in brain size, even if these were entirely of genetic origin, leave unexplained 91-95% of the black-white IQ gap. We highlight additional problems with hypotheses raised by Rushton and Templer. National IQs cannot be viewed solely in evolutionary terms but should be considered in light of global differences in socio-economic development, the causes of which are unknown.

A systematic literature review of the average IQ of sub-Saharan Africans

Jelte M. Wicherts, Conor V. Dolan a and Han L.J. van der Maas a

a Department of Psychology, Psychological Methods, University of Amsterdam, Roetersstraat 15, 1018 WB Amsterdam, The Netherlands

Received 8 October 2008; revised 6 May 2009; accepted 12 May 2009. Available online 9 June 2009.

Abstract

On the basis of several reviews of the literature, Lynn [Lynn, R., (2006). Race differences in intelligence: An evolutionary analysis. Augusta, GA: Washington Summit Publishers.] and Lynn and Vanhanen [Lynn, R., & Vanhanen, T., (2006). IQ and global inequality. Augusta, GA: Washington Summit Publishers.] concluded that the average IQ of the Black population of sub-Saharan Africa lies below 70. In this paper, the authors systematically review published empirical data on the performance of Africans on the following IQ tests: Draw-A-Man (DAM) test, Kaufman-Assessment Battery for Children (K-ABC), the Wechsler scales (WAIS & WISC), and several other IQ tests (but not the Raven's tests). Inclusion and exclusion criteria are explicitly discussed. Results show that average IQ of Africans on these tests is approximately 82 when compared to UK norms. We provide estimates of the average IQ per country and estimates on the basis of alternative inclusion criteria. Our estimate of average IQ converges with the finding that national IQs of sub-Saharan African countries as predicted from several international studies of student achievement are around 82. It is suggested that this estimate should be considered in light of the Flynn Effect. It is concluded that more psychometric studies are needed to address the issue of measurement bias of western IQ tests for Africans.

The dangers of unsystematic selection methods and the representativeness of 46 samples of African test-takers

Jelte M. Wicherts, Conor V. Dolan a and Han L.J. van der Maas a

a University of Amsterdam, The Netherlands Received 13 October 2009; accepted 6 November 2009. Available online 3 December 2009.

Abstract

In this rejoinder, we criticize Lynn and Meisenberg's (this issue) methods to estimate the average IQ (in terms of British norms after correction of the Flynn Effect) of the Black population of sub-Saharan Africa. We argue that their review of the literature is unsystematic, as it involves the inconsistent use of rules to determine the representativeness and hence selection of samples. Employing independent raters, we determined of each sample whether it was (1) considered representative by the original authors, (2) drawn randomly, (3) based on an explicated stratification scheme, (4) composed of healthy test-takers, and (5) considered by the original authors as normal in terms of Socio-Economic Status (SES). We show that the use of these alternative inclusion criteria would not have affected our results. We found that Lynn and Meisenberg's assessment of the samples' representativeness is not associated with any of the objective sampling characteristics, but rather with the average IQ in the sample. This suggests that Lynn and Meisenberg excluded samples of Africans who average IQs above 75 because they deemed these samples unrepresentative on the basis of the samples' relatively high IQs. We conclude that Lynn and Meisenberg's unsystematic methods are questionable and their results untrustworthy.

Keywords: Systematic literature review; National IQ; Group differences in IQ

a Department of Psychology, Psychological Methods, University of Amsterdam, Roetersstraat 15, 1018 WB Amsterdam, The Netherlands

b University of California, Riverside, United States

Received 19 May 2009; revised 19 November 2009; accepted 3 December 2009. Available online 16 December 2009.

Abstract

This paper presents a systematic review of published data on the performance of sub-Saharan Africans on Raven's Progressive Matrices. The specific goals were to estimate the average level of performance, to study the Flynn Effect in African samples, and to examine the psychometric meaning of Raven's test scores as measures of general intelligence. Convergent validity of the Raven's tests is found to be relatively poor, although reliability and predictive validity are comparable to western samples. Factor analyses indicate that the Raven's tests are relatively weak indicators of general intelligence among Africans, and often measure additional factors, besides general intelligence. The degree to which Raven's scores of Africans reflect levels of general intelligence is unknown. Average IQ of Africans is approximately 80 when compared to US norms. Raven's scores among African adults have shown secular increases over the years. It is concluded that the Flynn Effect has yet to take hold in sub-Saharan Africa.

Jedi of Zen wrote:But regardless of the IQ question, it is already well established within the medical field that there are genetic differences between races, as evidenced by the likelihood of certain racial groups to develop certain kinds of diseases that can only be acquired primarily by genetic transmission. Example - Tay-Sachs disease is far common among Ashkenazi Jews than among the general population.

Jedi of Zen you are incorrect. The modern day concensus is that race exists as a purely social construct, mainly due to the fact that our contemporary ideas of racial classificaton are based exclusively on 19th century folk taxonomic principles that rarely at all correspond with modern day scientific studies based on wholistic population genetics. A good example that illustrates this fact, is the fact that many populations on the African continent that are generally regarded as "black" such as Somalis, Ethiopians and Sudanic groups such as the Beja, are in fact genetically closer to Eurasian populations than they are to other black Africans. See studies:

East Africans are more related to Eurasians than to other African populations.1, 2, 3 Investigations of Y chromosome markers have shown that the East African populations were not significantly affected by the east bound Bantu expansion that took place approximately 3500 years ago, while a significant contact to Arab and Middle East populations can be deduced from the present distribution of the Y chromosomes in these areas.

Non sub-Saharan African samples are all grouped together…with…the Ethiopian Amharic sample [on the Y-chromosome]. Ethiopians are not statistically differentiated from the Egyptian and Tunisian samples, in agreement with their linguistic affiliation with the Afro-Asiatic family.” The occurrence of E*5 212 and E*5 204 alleles in two populations of the Mediterranean basin (Turkey and Italy) but not in West Africans can be explained by taking into account that the Ethiopian gene pool was estimated to be >40% of Caucasoid derivation (Cavalli-Sforza et al. 1994). In addition, more recent phylogenetic analysis based on classical protein polymorphism (Tartaglia et al. 1996) and Y-chromosome sequence variation (Underhill et al. 2000) showed that Ethiopians appear to be distinct from Africans and more closely associated with populations of the Mediterranean basin.

And medical practioners do not speak about "race" differences in the epidemiology of different diseases, rather they speak of population differences in the prevalence of such diseases:

The confused nature of this debate is apparent when we recognize that although everyone, from geneticists to laypersons, tends to use “race” as if it were a scientific category; with rare exceptions, no one offers a quantifiable definition of what a race is in genetic terms. The free-floating debate that results, while entertaining, has little chance of advancing this field. What is at stake is a more practical question — namely, has genomics provided evidence that race can act as a surrogate for genetic constitution in medicine or public health? Our answer is no. Race, at the continental level, has not been shown to provide a useful categorization of genetic information about the response to drugs, diagnosis, or causes of disease.

The modern day concensus is that race exists as a purely social construct, mainly due to the fact that our contemporary ideas of racial classificaton are based exclusively on 19th century folk taxonomic principles that rarely at all correspond with modern day scientific studies based on wholistic population genetics.

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vsdfa wrote:The modern day concensus is that race exists as a purely social construct, mainly due to the fact that our contemporary ideas of racial classificaton are based exclusively on 19th century folk taxonomic principles that rarely at all correspond with modern day scientific studies based on wholistic population genetics.

What vsdfa said isn't true. Races are experimentally verifiable, biological realities. They are not social constructs.

A social construct is something like "human dignity," which exists only because people agree to behave as if it did. But when faced with forces that don't share that agreement, such as an enemy, a hungry wild animal, or an elemental force of nature, most people quickly realize that "human dignity" isn't really a fact of nature, but is rather a human fiction, which offers no protection at all for the simple reason that it has no physical existence.

The idea that race might be a social construct began as a hypothesis introduced by Richard Lewontin, a Harvard geneticist, in 1972. He claimed that the genetic differences between races were so slight that no one working only with genetic data would categorize people as Asians, Whites, Blacks, Mestizos, etc. Lewontin said that racial classification "is now seen to be of virtually no genetic or taxonomic significance."

Leftist racial egalitarians were quick to pick up on Lewontin's words and create a number of chants and slogans from them, including "Race is a social construct" and "There's only One Race, the Human Race." The Lewontin Hypothesis almost immediately became a required belief among the politically correct. Unfortunately for them, less than 30 years later it became possible for geneticists and forensic scientists to conduct a statistical analysis of genetic markers in order to see whether their clusters correlated with the commonly identified racial groups.

They did. By 2005, it was well documented that Lewontin had been wrong. Practically every analysis of genetic markers demonstrated the biological reality of racial identities. In one of them, conducted by Tang, Quertermous, and Rodriguez, et. al., in 2005, all except five of 3636 test subjects (including Asians, Whites, Blacks and Mestizos) sorted statistically into the cluster of genetic markers that corresponded to their self-identified racial group. The success rate for predicting how someone would classify himself racially, using only his genes as information, was approximately 99.9 percent, according to that study.

It had long been possible for physical anthropologists to sort skeletal remains by race with very good accuracy, using only the shapes of skull, jaw, teeth and bones as guides. By the first years of the 21st century, it had become possible for forensic experts to do the same thing with DNA, which enabled more accurate identifications of fathers in paternity disputes and in showing police when they have arrested the right suspect, or, sometimes, when they'd nabbed the wrong fellow.

But leftists are even worse than sophomores when it comes to suffering correction. They have the pugnaciousness to call people who are much more informed than they are themselves, "ignorant." They've adopted the "social construct" slogan, and, come what may, they're not ever going to give it up. They will simply keep on using that slogan in lieu of evidence again and again.

Anyone who has followed race-related discussions for long has noticed a peculiarity in the manner in which “racial equality” proponents argue. You can even see it here, in this discussion. They never bring forward positive evidence for racial equality. Or, at least, I haven’t seen them attempt to do so. They behave as if equality were given, already proved—by persons unknown, at a time and place unmentioned, by measurements unspecified. It’s one of those things that “everyone” is supposed to “know.” In debate, or in peer review "rejoinders," they never disclose any countervailing data. Rather, they confine themselves to picking nits in the completeness of their opponents' information, or to claiming to find flaws in their opponents' analyses. The rhetoric of racial equality proponents rather reminds one of Creationists, trying to cast doubt upon the theory of evolution.

As the result of the experimental falsification of the Lewontin Hypothesis, hence the verification of race in humans as a biological reality, the leftist theory of racial equality is now in the position that modern astronomy imposed upon the doctrine of the medieval Church. As the evidence for a sun-centered solar system kept mounting, those who clung to the old Earth-centered paradigm began looking sillier and sillier. Eventually—meaning after 400 years of intransigence—a Pope admitted that Galileo had been right all along and that the former Church position had been in error. That's probably more graciousness than we'll ever see from the dogmatic leftists on the subject of race.

Really, the idea of racial equality ought to have been suspect in any reasonable person's mind from the beginning. Nature produced the visible racial differences, which we usually notice on inspection, and which we mostly agree are trivial. But then the leftists declared that those "cosmetic" racial differences were the only differences between the races. It would be a very strange thing indeed if nature, which created all of the heritable traits in organisms, had been aware of leftist sensibilities since the dawn of time, and had taken great care—with humans—to permit the evolution of only those racial differences having no social significance of which leftists might disapprove.

The arguments of racial separatists, persons who look askance at multiracial societies and prefer the company of their own kind, are not without merit. Rather than repeat those arguments in racial terms, allow me to make a simple analogy. Races may be compared with metal canisters filled with gas. The net effect of their collective behavior is like the temperature of the canisters. You can measure their temperatures in order to find out whether they are inside a safe-handling range. If you forgo testing the temperature, or if you are informed about the temperature but choose to disregard any "too hot to handle" warnings, then you risk being burned.

However, temperature does not predict the speed of any particular molecule in the canister. It only tells you what the average speed is. Likewise, statistics on HIV infection rates, crime rates, IQ scores, and similarly important subjects, broken down by race, might tell us that a certain race is, in general, a rather nasty bunch of savages, even though we realize that there are bound to be exceptions. The existence of those exceptions does not justify or require our making overtures to persons belonging to such a race, or going over to them and associating ourselves in such a way that we will be burned.

That's a good analogy Jenab6. I'm going to start using yours, instead of the one I have been using.

Add me to the group that considers it established that intelligence is genetic (polygenic trait) and average intelligence varies with race. I don't think brain size is a very exact measure, it's not good for much more than saying "Okay homo erectus was probably less intelligent than h. sapiens."

Some of the research coming out these days is really fascinating, just a month ago this was publishedRare copy number deletions predict individual variation in intelligence.http://www.ncbi.nlm.nih.gov/pubmed/21298096

The sum total length of deletions is inversely related to intelligence; white/Anglo group was compared to "other" and found to be more resistant to the effect of deletions.

Why is it that everyone of you go all out to try to prove that there can not possibly be a difference in IQ between races? Better yet why is it that you think it is racist to think this? When I have never seen a study trying to prove that blacks are superior to all other races athletically questioned? Have you ever thought racism could come into the second hypothesis?